Natural interferon-beta treatment and steroid hormone receptors in primary endometrial cancer.

Forty-three patients with primary endometrial carcinoma were treated with natural interferon-beta (IFN-beta) at two different dose levels (2 x 10(6) IU or 6 x 10(6) IU im 3 times/week for 1 week). IFN-beta increased receptors for estrogens (ER) and progesterone (PR) in a high percentage of the 40 evaluable patients, without modifying the receptor affinity. The ER and PR enhancement, which was simultaneous in at least 50% of patients, and the increase of over 100 fmol/mg protein observed in some cases suggest that IFN-beta exerts a profound influence on receptor expression and, probably, on the hormone sensitivity of the tumor.